Enteral adenoviruses are a recently discovered group of agents which cause gastroenteritis in children. They differ from all other known human adenoviruses in their inability to be propagated in tissue culture. During the past year we have established channels to obtain specimens containing these unusual agents. Stool specimens have been characterized by enzyme immunoassay, electronmicroscopy, and attempted propagation in tissue culture. These agents have been studied to determine the biological basis for their inability to grow in tissue culture. Immunofluorescent microscopy, complementation experiments utilizing a variety of other viruses, sucrose gradient and DNA hybridization analysis have been performed to probe the biochemical events in enteral adenoviral infection. In summary we have learned that these agents induce an abortive infection which is abruptly terminated at a very early step of the virus growth cycle.